This invention relates to picking devices for mechanical harvesters.
Harvesting machines which straddle a row of plants, such as grape vines, and move along the row to harvest the fruit thereon are now well known. Mounted on the frame and suspended therefrom are picking devices which engage the plants and remove the fruit therefrom. The picking device to which the present invention pertains is the pivotal striker type wherein a pair of opposed, vertical striker rod holders are mounted, one on each side of the machine, each striker rod holder having a plurality of vertically-spaced resilient striker rods mounted on and extending horizontally from the rod holder. Suitable drive mechanism is provided to oscillate the rod holders about their vertical axes, so that the striker rods pivot about such axes with the tips of the rods being moved back and forth, towards and away from the centerline of the machine.
Typically, the striker rods are operated in wigwag manner, with one set of rods moving towards the centerline of the machine while the other set of rods moves away from the centerline on the opposite side thereof.
The actual harvesting is accomplished with such picking mechanism as a result of the striking impact of the striker rods as they are moved inwardly and hit the sides of the plants, and/or the fruit growing thereon, first on one side of the plants and then on the other side.
Typically, the harvesting machines will move along the rows of plants at a ground speed of from 2 to 3 miles per hour, with the striker rods being operated to deliver 300-400 strikes per minute.
Often, a second set of opposed striker rods is included in the picking device, spaced longitudinally from the first set to provide a second striking action on the plants.
For maximum harvesting efficiency, the picking device should be adjusted to the particular variety of plants being harvested since different varieties of plants will require different amounts of striking force thereagainst for optimum fruit removal. If less striking force is used, less fruit removal will result. If a greater striking force is applied, the amount of fruit removal will not increase to any significant degree, but plant damage and leaf removal will increase. Leaf removal is undesirable, since such leaves must then be separated from the harvested fruit.
Typically, pivotal striker mechanisms are manually adjustable so that the stroke of the striker rods, i.e. the distance between the innermost and outermost excusion of the rods during operation, can be varied in accordance with the variety of plant being harvested. In addition, the spacing between the centerline of the machine and the innermost excusion of the striker rod tips is also manually adjustable so that such spacing can be set in accordance with the width of the plants to enable the rod tips to strike against the fruit bearing portion of the plants. Such adjustments are made prior to harvesting a particular vineyard and, once set, the adjustments remain the same during harvesting.
A common problem in a harvesting operation is that the machine and striker rods thereon will not remain centered on the fruit bearing portions of the plants as the machine moves down a plant row. Oftentimes this is caused by careless steering of the machine by the operator. In other instances the plants will be supported by posts and be planted in an area where there is a sufficient prevailing wind such that the posts will all be inclined from vertical. The operator may steer the machine down a row, centering the machine on the tops of the posts which are visible above the plant foliage, but with the result that the fruit bearing portion of the plants are actually off-set from the tops of the inclined post. Another problem is centering a machine on a row of plants is that when the row has an east-west orientation, the foliage will be heavier on the south, or sunny, side of the plants so that the center of foliage is off-set from the fruit-bearing zone of the plants.
Regardless of the reason why a machine may be offset from the fruit bearing zone, when this occurs one side of the fruit bearing portion of the plants will be struck with more force than the other. Excessive plant damage and leaf removal will occur on one side of the plants, while reduced fruit removal will occur on the other.
As a consequence, there is a need for a pivotal striker rod picking device which will automatically center the striking action of the rods on the fruit-bearing portions of the plants, with equal striking force being applied to each side of the plants, even though the centerline of the fruit-bearing portions are offset from the center line of the machine.
Another problem in harvesting is that oftentimes the width of the plants will vary along a row. For example, many vineyards have relatively large vine trunks spaced along a row with the fruit-bearing canes trained along wires extending between the trunks. If the striker rods are set to strike against the relatively narrow fruit-bearing zone along the wires, then the rods will strike with an undesirably great force against the relatively large trunks as the machine moves throughout, such that excessive plant damage and striker rod breakage will occur. If, however, the machine is set to accommodate the width of the trunk, inefficient harvesting of the fruit-bearing canes between the trunks will result.
As a consequence, there is a need for a striker rod picking device which will automatically vary the tip spacing between opposed striker rods in accordance with variations in plant width so that a uniform maximum striking force will be applied to the plants along the length of a row.
Another inadequacy of present pivotal striker rod picking devices is that single-pair and twin-pair devices are separate devices, separately manufactured and installed. This has resulted in a lack of flexibility in the manufacture and use of harvesting machines equipped with pivotal striker picking devices.
There is a need for a single unit striker rod picking device that can be easily changed from use with one pair of opposed striker rods to two pairs thereof, and vice-versa. There is also a need for a striker rod picking device equipped with two pairs of opposed striker rods wherein the wig-wag movement of the two pairs of striker rods can be easily changed from an in-phase relation to an out-of-phase relation, and vice-versa.